All engines have many moving parts that require lubrication to minimize friction when the engine operates. The lubrication allows the engine to work more efficiently and with reduced wear and tear. Lubricants not only lubricate the moving parts, but also cool the engine, inhibit corrosion, collect dirt, metal debris, soot and other particulates that damage the engine.
Very early motor vehicle engines did not have oil filters, allowing the engine oil to quickly become contaminated. The oil had to be changed frequently. After World War I, a bypass filter system was developed for the automotive engine. An oil pump forced a gross unregulated output into a plurality of distribution passages within the engine and controlled oil pressure downstream through a regulator. All of the oil was pumped directly from the oil reservoir by an oil pump to the moving parts without filtration, and in the bypass filtration, a smaller proportion of the oil was sent through the bypass filter and returned directly to the reservoir. Particulates not caught by the filter continued to circulate with the oil. The relatively basic lubricating oil was primarily hydrocarbons from petroleum, and had to be changed frequently to remove accumulated contaminants.
Development of performance-enhancing additives for lubricating oil began in earnest during World War II. Their specially designed properties allow a wider temperature range with measurably better viscosity performance at service temperature extremes. Additionally, contemporary lubricating oils have better chemical stability, being resistant to oxidation and thermal breakdown and better shear stability when compared to the traditional oils. Contemporary oils on the market also have additive compounds such as detergents and surfactants that suspend particulate so that they are delivered to a filter in the oil distribution system. Most particulates do not settle out in the reservoir; instead, they continue to circulate as oil contaminants until captured within an oil filter.
Since these contemporary oils last longer in terms of physical and chemical stability, the need to change the oil is less frequent. With less frequent oil changes, the particulates accumulate, offsetting certain advantages of the contemporary oils. If the oil is recirculated without complete filtering, as in the bypass filter system or when there is no oil filter system, the suspended particulates accelerate engine wear and tear.
To avoid the detrimental effects of unfiltered, contemporary oils on very early motor vehicle engines, better filtering of the oil is required so that particulate build-up is minimized. Newer automobiles employ a full-flow system, wherein all of the oil passes through the oil filter system in a single flow path, the oil moving from the oil reservoir to the engine by first moving through the filter. Older motor vehicles with the bypass system or without a filter system cannot take full advantage of the higher performing contemporary oils. Although the old-fashioned lubricants are still on the market, car enthusiasts who operate older automobiles having the bypass system or no filter system desire to use contemporary engine oils. However, without a full-flow filter system, they are limited to the use of old-fashioned products or with misuse of contemporary oils.
Some have seen the advantage of a full-flow system for older automobiles and have developed a way to retrofit air-cooled engines with a full-flow system. While these retrofit units may be suitable for the particular purpose employed, or for general use, they would not be suitable for the purposes of the present disclosure as disclosed hereafter. None, however, have converted a no-filter system or a bypass system into a full-flow system for retrofitting the older motor vehicle engine and thereby permit safe use of contemporary oils.
In the present disclosure, where a document, act or item of knowledge is referred to or discussed, this reference is not an admission that the document, act or item of knowledge or any combination thereof was at the priority date, publicly available, known to the public, part of common general knowledge or otherwise constitutes prior art under the applicable statutory provisions; or is known to be relevant to an attempt to solve any problem with which the present disclosure is concerned.
While certain aspects of conventional technologies have been discussed to facilitate the present disclosure, no technical aspects are disclaimed and it is contemplated that the claims may encompass one or more of the conventional technical aspects discussed herein.